Intramolecular Noncovalent Interactions in Bis-Imidazolium Dications with Short Aliphatic Spacers

Stretched all- trans conformations were found preferable in computed structures of bis-imidazolium dications with short aliphatic (С 1 –С 4 ) and hydroxyl substituted –СН 2 –СНОН–СН 2 – bridges. The molecular electrostatic potential is distributed unevenly in the dications: maxima of molecular electrostatic potential are located near С 2 Н imidazolium and bridge hydrogens for the α,ω-alkenyl bridges, and close to hydroxyl hydrogen for the hydroxypropane bridge. Intramolecular hydrogen bonds С–Н···ОН contribute to a significantly higher rotational barrier around С 1 –C 2 bond in dications with a hydroxypropane bridge compared with polymethylene bridges.